Fungicidal composition therefor



fittes METHOD FOR COIVIBATING FUNGUS AND FUNGICIDAL COMPOSITION THEREFOR No Drawing. Application May 1, 1957 Serial No. 656,182

9 Claims. (Cl. 16730) This invention relates to the combating of fungus. More specifically this invention is directed to a method of combating fungus involving the use of fungicidal compositions containing as an active ingredient tetrachlorocyclopentadiene such as, for example, 1,2,3,4-tetrachlorocyclopentadiene. Additionally the invention is concerned with the fungicidal compositions themselves.

It has now been found that fungus or fungi can be very effectively combated or controlled by applying tetrachlorocyclopentadiene to the locus to be protected from fungus. Living plants are protected by virtue of this invention without injury thereto. Application of the fungicide to host or potential host plants can be effected by spraying or, if desired, by dusting or by other suitable means. The 1,2,3,4-tetrachlorocyclopentadiene is preferred for use herein.

The active fungicidal agent, i.e., tetrachlorocyclopentadiene is advantageously utilized in this invention together with a suitable carrier or diluent to provide compositions in the form of aqueous dispersions or emulsions, water-dispersible powders, solutions, or dusts. Aqueous dispersions containing tetrachlorocyclopentadiene .such as 1,2,3,4-tetrachlorocyclopentadiene can be prepared by first dissolving this 1,2,3,4-tetrachlorocyclopentadiene in an inert liquid solvent such as acetone. Other suitable inert liquid solvents that may be utilized instead of acetone and which may be miscible or immiscible with water include methanol, methyl ethyl ketone, glycol ethers, xylene and methylated naphthalenes. Typical con centrations of tetrachlorocyclopentadiene in solutions prepared utilizing the foregoing solvents will contain from about 0.5% to 15%, say 1% by weight of this tetrachloro compound based on the weight of the solution. Thereafter this solution is diluted or admixed with water to form an aqueous dispersion suitable for spray application. Dilution of from 1 part to 1000 parts of tetrachlorocyclopentadiene per 1 million parts of water and solvent have produced excellent results in combating fungus.

Suitable emulsifying or wetting agents can be added to the foregoing aqueous dispersions of tetraehlorocyclopentadiene, if desired, which serve to maintain the mixture as an oil in water emulsion. Small percentages such as from about 3% to 10% of emulsifying agent will sufiice.

Typical emulsifying agents include materials marketed under the trade names Atlox 4500 and Atlox 4600 and defined in the literature as blends of alkyl aryl sulfonates with polyoxyethylene sorbitan esters of mixed fatty and resin acids. Also emulsifying agents defined in the literature as blends of alkyl aryl polyether alcohols with organic sulfonates, such as blends of Triton 151 and Triton X 171, and as blends of polyether alcohols with organic sulfonates such as Emco H-85X can be used. Other emulsifying or wetting agents that can be used are the alkali metal, e.g. sodium, salts of decyl, dodecyl, tetradecyl or octadecyl benzene sulfonic acids.

Solid dry carriers or powders such as bentonite, wood tent flour, kaolin, and chalk may also be mixed with tetrachlorocyclopentadiene such as the -l,2,3,4-tetrachloro compound to produce fungicides suitable for application by dusting. Dusting powders of this type will typically contain from about 1% to 15%, say 7.5% by weight of the active fungicidal agent. Such powders may also contain in known mixture suitable quantities of wetting agents.

Water-dispersible powders can be prepared by grinding or reducing tetrachlorocyclopentadiene, which is a nearly white solid, together with appropriate solid dry carriers as mentioned above and suitable wetting and dispersing agents to a typical particle size'of from about 1 to 30 microns. Alternatively, the water-dispersible powder can be made by impregnation of the toxicant on the solid carrier or powder from a solution in any appropriate solvent, such as those mentioned above. Thereafter the finely divided particles are admixed with water to form the dispersion.

The active fungicidal agent, which is tetrachlorocyclopentadiene, can be prepared by the reduction of hexachlo-rocyclopentadiene with zinc at a temperature not in excess of C. It is a white crystalline solid melting at 62-63 C. This synthesis of tetrachlorocyclopentadiene is described by Danish, Silverman and Tajima in J. Am. Chem. Soc. 76, 6149 (1954).

The following example in which parts are by weight unless otherwise specified illustrates a specific method of preparing tetrachlorocyclopentadiene.

A mixture of 819 parts of hexachlorocyclopentadiene and 1350 parts by volume of glacial acetic acid was stirred vigorously in a 3 liter, 3 necked flask fitted with a thermometer and reflux condenser while 450 parts of zinc dust were added thereto over a 30 minute period. The reaction was extremely exothermic and the temperature of the reactants was kept below 75 C. with a'Dry Ice-acetone bath. Stirring was continued for 30 minutes after the addition of all the zinc dust. The reaction mixture was then filtered free of excess zinc dust and the filtrate was poured into 4500 parts by volume of water. The resulting oily phase solidified in 2 hours. The solid material was then filtered from the liquid phase and this solid material was then dissolved in 2000 parts by volume of ligroin at a temperature of 5060 C. The ligroin solution was then dried over anhydrous calcium chloride and evaporated under reduced pressure to a small volume. On cooling, a first crop of 273 parts of wet crystals was obtained by filtration and a second crop of 65 parts of Wet crystals was also obtained. 162.9 parts of filtrate which was a reddish brown oil remained. Two recrystallizations of the first and second crops of crystals from hexane gave 175 parts of white crystals, M.P. 61.6-62.4 C. A part batch of these crystals was recrystallized again from methanol and white tetrachlorocyclopenta diene crystals were obtained which melted at 62.6- 62.8 C.

Analysis.Calculated for Cl=69.56%. Cl=68.48%.

The fungicidal compositions of this invention serve not only to destroy fungus or fungi existing on organic-matter such as plants, etc., but also serve to prevent the fungi from approaching or feeding on the organic matter which has been treated therewith.

The importance of the present invention and the technical advance afforded thereby will be appreciated from the following tests.

Spore germination tests were conducted using Sclerotinia fruczicola (brown rot of stone fruits) and Stemphylium sarcinaeforme (target spot of clover).

The fungicides of this invention prepared as indicated above were dissolved in acetone in a concentration of 1% based on the weight of the total solution. This Found for Patented Aug. 11, 1959 solution of fungicide was then diluted with water in the water to fungicide solution ratio of 9:1 respectively to provide a concentration of 1000 parts of each fungicide per million parts of water plus acetone. Serial 9:1 dilutions were also employed to provide concentrations of 100 parts, parts, and 1 part of fungicide per million parts of water plus solvent, respectively. Sclerotinia fructicola spores were added to one series of dilutions while Stemphylium sarcinaeforme spores were added to the other series. Following an incubation period of 24 hours at 65 F. the fungicide containing solution was examined under the microscope to determine average percent germination of spores for each fungus at each concentration. These tests were compared with a series of similar fungus containing solutions of water alone and of water containing fungicidally effective concentrations of copper sulfate. The following results were obtained.

Tests were also conducted for protection against the apple scab fungus on live McIntosh apple plants or trees of from 6 inches to inches tall. A fungicidal solution of 0.1% concentration by weight in acetone and water of tetrachlorocyclopentadiene prepared as described above was sprayed on the apple plants to cover the foliage with fine droplets. About to 30 cc. of solution per plant was used.

Inoculum of Venturia inaequalia conidia were obtained from active lesions on apple leaves from plants infected with the same and were then atomized onto the sprayed plant after the spray had dried.

The amount of apple scab infection was recorded 14 days after the date of inoculation with the fungus during which the plants had been subjected to high humidity and temperature conducive to germination of the fungus. The number of plants which showed infection and the estimated percentage of the leaf area that was infected were recorded at this time and compared with data noted with respect to plants which were subjected to substantially identical conditions except that the fungicide of this invention was not applied to them. The plants which had been sprayed were not injured. The following results were obtained.

Infection with apple scab Tests were also conducted for protection against tomato late blight on live window box tomato plants of from about 4 to 6 inches tall. A fungicidal solution of tetrachlorocyclopentadiene prepared as is previously described in acetone and water was applied to the foliage of the tomato plants by spraying utilizing a substantially identical concentration of tetrachlorocyclopentadiene and spraying procedure as is described above with respect to protection tests against apple scab. -Approximately 20 to 30 cc. of fungicidal solution per plant was utilized.

An inoculum of Phytophthora infestans zoospores, which are pathogenic to tomatoes, were then atomized onto the sprayed plants after the spray had dried.

The amount of plant defoliation was recorded 7 days Tomato late blight tests Percent defoliation Plant Plant Plant Aver- No. I No. II No. III age Tetrachlorocyclopentadiene.... 0 0 0 0 Untreated 50 40 60 60 Tetrachlorocyclopentadiene such as the 1,2,3,4-tetrachloroisomer tends to undergo oxidative deterioration and darken on exposure to air and light for a substantial time, and also dimerize on exposure to heat. 1,2,3,4- tetrachlorocyclopentadiene can be kept for several weeks in Well filled brown bottles at room temperature without chemical change. If this tetrachlorocyclopentadiene is not to be applied, as previously described, to the locus or plant to be protected from fungus for a prolonged period of say several weeks or more, formulations containing it should be stabilized against these effects. Addition of a minor amount, e.g., 0.5 to 1% by weight (based on the weight of the tetrachlorocyclopentadiene), of a stabilizing agent of the group consisting of alpha naphthol and 2,6-ditertiarybutyl-para-creso1 to the fungicidal composition, e.g. a dilute solution (e.g. of 25% concentration) or a concentrated solution (e.g. of concentration) of tetrachlorocyclopentadiene in xylene will elfectively stabilize the tetrachlorocyclopentadiene against chemical change as discussed above. If desired, the previously discussed solutions containing tetrachlorocyclopentadiene and stabilizing agent can be combined with water to form aqueous dispersions, preferably with the aid of a minor amount, e.g. 5%-l5% by weight (based on the weight of the solution), of a suitable emulsifying agent such as, for example, Triton X-l55, which is an alkyl aryl polyether alcohol. The stabilizing agent does not chemically combine with the tetrachlorocyclopentadiene. The stabilizing agent can also be incorporated into the previously discussed tetrochlorocyclopentadiene powders, such as the water-dispersible powders, by impregnating the solid, powder form carvrier with a previously discussed solution of the alpha naphthol or 2,6-ditertiarybutyl-para-cresol in a suitable solvent such as xylene. This solution should be of a concentration sufficient to add or incorporate the desired minor stabilizing amount of stabilizing agent into the powder. Application of the formulations containing tetrachlorocyclopentadiene and stabilizing agent discussed above to the locus or plants to be protected by the methods previously discussed results in a highly effective combating and destroying of the particular unwanted fungus or fungi.

What is claimed is:

l. A fungicidal composition adapted for combining with a diluent for application, which comprises tetrachlorocyclopentadiene as active ingredient, and a minor amount suflicient to stabilize the tetrachlorocyclopentadiene against oxidative deterioration of an antioxidant of the group consisting of alpha naphthol and 2,6-ditertiarylbutyl-para-cresol.

2. A fungicidal composition. comprising l,2,3,4-tetrachlorocyclopentadiene as active ingredient, a carrier for the tetrachlorocyclopentadiene, and a minor amount suflicient to stabilize the tetrachlorocyclopentadiene against oxidative deterioration of a material of the group consisting of alpha naphthol and 2,6-ditertiarybutyl-paracresol.

3. A fungus control composition adapted for dispersion in water to form a spray for plants, which comprises 1,2,3,4-tetrachlorocyclopentadiene as an active ingredient, a minor amount, suificient to stabilize said tetrachlorocyclopentadiene against oxidative deterioration, of a stabilizing agent of the group consisting of alpha naphthol and 2,6-ditertiarybutyl-para-cresol, and xylene as solvent for said tetrachlorocyclopentadiene and said stabilizing agent.

4. A method of protecting plants against attack by fungi, which comprises applying a fungicidal composition comprising as active ingredient tetrachlorocyclopentadiene and a diluent therefor to the plant to be protected.

5. A method of combating fungi which comprises applying tetrachlorocyclopentadiene to a plant susceptible to attach by fungus.

6. A method of combating fungi which comprises applying a fungicide comprising as active ingredient 1,2,3,4- tetrachlorocyclopentadiene and a diluent therefor to a plant susceptible to attach by fungus.

7. A method of combating fungi which comprises applying to a plant susceptible to attack by fungus a fungicide comprising a carrier, 1,2,3,4-tetrachlorocyclopentadiene as active ingredient, and a minor amount suificient to stabilize the tetrachlorocyclopentadiene against oXidati-ve deterioration of a material of the group consisting of alpha naphthol and 2,6-ditertiarybutylpara-cresol.

8. A method of protecting apple trees against attack by apple scab, which comprises applying an aqueous fungicidal dispersion comprising as active ingredient 1,2,3,4-tetrachlorocyclopentadiene dispersed in an aqueous liquid carrier therefor to the apple tree to be protected.

9. A method of protecting tomato plants against attack by tomato late blight, which comprises applying an aqueous fungicidal dispersion comprising as active agent 1,2,3,4-tetrachlorocyclopentadiene dispersed in an aqueous liquid carrier therefor to the tomato plant to be protected.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2,899,355 August 959' Edward R0 Degginger cal},

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, lines 20 and 24, for "attach", each occurrence, read attack Signed and sealed this 23rd day of February 1960,

(SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Ofiicer Commissioner of Patents 

1. A FUNGICIDAL COMPOSITION ADAPTED FOR COMBINING WITH A DILUENT FOR APPLICATION, WHICH COMPRISES TETRA CHLOROCYCLOPENTADIENE AS ACTIVE INGREDIENT, AND A MINOR AMOUNT SUFFICIENT TO STABILIZE THE TETRACHLOROCYCLOPENTADIENE AGAINST OXIDATIVE DETERIORATION OF AN ANTIOXIDANT OF THE GROUP CONSISTING OF ALPHA NAPHTHOL AND 2,6-DITERTIARYLBUTYL-PARA-CRESOL. 